Antileak agent for greases



Patented Dec. 29, 1936 UNITED STATES PATENT OFFICE ANTILEAK AGENT FORGREASES William P. Hilliker, Hammond, Ind., assignor to Standard OilCompany, Chicago, 111., a corporation of Indiana No Drawing. ApplicationOctober 2'1, 1933, Serial No. 695,510

'7 Claims.

and aluminum soap greases so that they do not leak or separate duringstorage or use into a predominately oil phase and a phase higher in soapthan the original composition.

Heretofore cup greases have been prepared by mixing water, oil, andlime, in a steam-jacketed grease mixer. The fatty acid is then added andheat is applied. After an interval of about 40 to minutes, when thetemperature has reached 240-260 F., the soap is ready for mixing. About2% to 3% of water is added, and when the batch foams up it is drivendown by the addition of oil, the heat being abstracted by the additionof cold oil and by the vaporization of water so that the temperaturedrops to about 230 F. Oil is added until the batch contains about 25%soap, and during this interval the temperature drops gradually until itreaches about 205-210 F. If desired, the soap percentage may be reducedto about 15, and the batch should reach a temperature of about 180-190F. at this point. This process is about the same for fats as for fattyacids except that it requires 12 to'20 hours at 240-260" F. to effectthe saponification of the fats.

When calcium soap greases are stored for a period of six months or moreor used, the oils oftentimes tend to ooze out of the composition andrise to the top of said composition. This phenomenon is called leakage.The separated oil has the appearance of an oil which has been sweatedout of the grease and collects in pools or pockets in any depressionwhich forms on the surface of the grease. This differs from separationat high temperatures in that the oil which leaks may be stirred backinto the grease to form a homogeneous mass. When complete separation ofthe grease occurs, agitation or stirring will not efiect a homogeneousmass.

I have discovered that certain classes of organic compounds, when addedto greases containing calcium or aluminum soap, prevent leaking or thebreaking down of the grease into an oil phase and a thick semi-solidresidue. The

classes of organic compounds or anti-leak; agents which may be used toprevent this particular type of deterioration are the aminophenols,substituted aminophenols, alkyl aminophenols, aryl aminophenols, aralkylaminophenols, phenolic aromatic compounds such as the hydroxy benzenecompounds and polyhydroxy benzene compounds, alkyl amines and arylamines. Some of the amino 5 phenols may be represented by the generalformula:

wherein R represents a hydrogen atom, alkyl, aryl or aralkyl radical andR1 represents a hydrogen atom, alkyl, aryl or aralkyl radical.

My invention is concerned, therefore, with the preparation of greasecompositions containing calcium or aluminum soap which do not leakduring storage or use. These calcium or aluminum soap greases aregenerally referred to as cup 25 greases. The greases may be prepared byany of the conventional methods, for example, calcium or aluminum soapof an animal or vegetable fatty acid or oil is mixed with a mineral oilof 90 to 500 Saybolt viscosity at F., and a small 30 amount of water.The mixture is agitated and heated in a steam jacketed kettle to atempera ture of about 200-212 F. until a homogeneous mass is obtained.After the grease has been prepared, the anti-leak agent should be mixedthere- 3 with in amounts of 0.1% to 0.4%. A grease ofany desiredconsistency can be prepared by varying the soap content of thecomposition and/or using a low or high viscosity mineral oil. Generally,the soap content of the cup grease varies 40 from 5% to 25%. Othermethods for preparing cup greases will be found in the book by Klemgardon Lubricating Greases and my invention may be used in any cup grease.For example, the anti-leak agents may be used in the cup greasesdisclosed in my U. S. Patent No. 1,989,197, application for which wasfiled August 9, 1932 which describes a new cup grease comprisinghydrogenated fatty oils or hydrogenated fatty acids.

The following is an example of a formula for cup grease in which mystabilizing agents may be employed:

until the soap dissolves.

The viscosity of the mineral oil used in the general formula may varyfrom 85 to 500 Saybolt at 100 F., however, the cup greases which giveconsiderable trouble with leakage are those which contain mineral oilshaving a viscosity from 85 to about 400 Saybolt viscosity at 100 F. andfrom 5% to 20% of calcium or aluminum soaps. Instead of using mixedfatty acids in the above formula, other high molecular, weight-.fattyacids, saponifiable fats and fatty oils and mixtures of the same may beused, for example, tallow, lard oil, cocoanut oil, castor oil, corn oil,palm oil, soy bean oil, oleic acid, and the like and mixtures thereof.

As another example of my invention the following formula for cup greasesmay be used:

. Lbs. Tallow 12.55 Cottonseed fatty acids 3.10 Hydrated lime 1.97Caustic soda 0.13

Paraffin oil (Saybolt viscosity 80 at 100 F)- 80.90 Water 1.70 Anti-leakagent (dimethyl amine) 0.2

As stated hereinbefore, my anti-leak agents can be used in cup greasescontaining aluminum soaps of fatty acids. These greases can be preparedby adding an aluminum soap to an oil, stirring until smooth, heatingwith steam to 200 to 400 F. The composition can be cooled slowly orrapidly in thin films, or stirred down to a lower temperature, or watercan be added, depending upon the type of grease desired. The anti-leakagent should be added after dissolving the soap.

Samples of cup greases of a consistency of about 316 as taken by the A.S. T. M. penetrometer at 77 F., containing about 13% of calciummixedfatty acid soaps in mineral oils of 300 Saybolt viscosity at 100 F.,were stabilized with about 0.15% of various different anti-leak agentsand stored for 17 months at room temperatures and then given anadditional storage of 12 months at 150 F. The following table gives theresults ob-- tained with the respective anti-leak agents:

I: monthts Aiditlonal s orage a s orage Anti leak agent room tem- 12months perature at 150 F.

Control (no anti-leak agent) Leakage--. Leakage. Paramethyl aminophenolNoleakage Noleakage. Para aminophenol do Do. Parabenzyl aminophenol do.Do. Hydrnfllflnnnn fin Very slight leakage. i-hydroxyl diphenyl -.do..--Do. Ortho r'r nl do Do. Al ha nnnhfhnl do Do, Diphenyl amine do... Do.Dibenzyl amine do.. Do. Dimethyl amine .do Do.

The term leakage is used in the above table to describe the condition ofthe cup grease at theend of the storage period, and indicates that aportion of the oil in the grease composition has risen to the top of thegrease or separated from the grease.

Other compounds which can be used for the purpose of my invention areethyl aminophenols, para diethyl and dipropyl aminophenols, phenylaminophenols, tolyl aminophenols, para phenyl aminophenols, dibenzylaminophenols, Z-methyl. amino l-naphthol, aminonaphthols, alkylatedpolyhydroxy benzene compounds, tertiary butyl catechol, catechol, paracresol, amino cr'esols, dibutyl amine, alkylene polyamines, propylenepolyamine,,and the like. The anti-leak agents should not contain anythio groups. However, sulphur per se can be used with reasonablesuccess. as an anti-leak agent.

I am aware of the use of anti-oxidants in compositions which tend tooxidize on storage, however, the action of the anti-leak agents cannotbe explained upon the theory of oxidation.

Although my invention has been illustrated by the use of specific greasecompositions and antileak agents, it should be understood that othermodifications may be used without departing from the scope of thefollowing claims.

I claim:

1. An improved grease composition comprising a homogeneous mixture of amineral oil, about to about 20% of a calcium soap of a high molecularweight fatty acid, and a small proportion of an anti-leak agent notexceeding 0.4%, containing no thio groups, which prevents the separationof oil from said grease, said anti-leak agent being an organic arylcompound having prevents the separation of oil from said composi-- tion,said anti-leak agent being an unneutralized phenolic compound.

3. An improved cup grease comprising 011, calcium soaps and not morethan about 0.4% of an anti-leak agent, containing no thio groups, whichprevents the separation of the oil from said grease, said anti-leakagent being an aminophenol.

4. An improved grease composition comprising a substantially homogeneousmixture of an oil, calcium soaps, and a small proportion of an antileakagent, containing no thio groups, which prevents the separation of oilfrom said grease, said anti-leak agent being an aminophenol of thegeneral formula quantity of an anti-leak agent not exceeding about 0.4%,said anti-leak agent being a. substituted aminophenol and containing nothio groups.

6. An improved grease composition comprising a substantially homogeneousmixture of a mineral oil, calcium soaps of high molecular weight fattyacids, and a small proportion of an anti-leak agent not exceeding about0.4%, containing no thio groups, which prevents the separation cf oilfrom said grease, said anti-leak 10 agent being an aminophenol whereinone amino hydrogen has been substituted with an organic radical.

7. The process of preventing a cup grease containing calcium soaps fromseparating into a predominately oil phase and a predominately soap phaseduring storage or use which comprises incorporating into said grease notmore than 0.4% of an aminophenol, containing no thio groups, whichprevents'said phase separation.

WILLIAM P. HILLIKER.

